I am a beginner--think I always will be, but am so excited about knitting. This is my first "thread". I have such a hard time fixing mistakes and usually have to get in my car and drive to the knitting store!!!

I am doing a scarf that is supposed to have 23 stiches; on my current row, I have 24 and think it's because I did an extra yarn-over. How do I get rid of it? All help is greatly appreciated.

If you can find the extra YO, you can let it slide off your needle with no ill effect. If you've already worked it somewhere, then you can do what Suzeeq said.

If you haven't done anything to that row yet, look at the stitches on the needle. You should have the pattern going of the first k, then a yo and the k2tog. They look different, so you should be able to tell which one doesn't belong. If it's just a yo, let it slide off the tip of the needle. It will seem loose there for bit, but it will even out.